Only 1 cabin class available as this is the standard across east African airlines.
Planes are much smaller than international commercial carriers and therefore all passengers get the same amount of legroom but they also all the best views. Aircraft operated by regional airlines are generally too small and the number of passengers they can carry too few to allow more than 1 cabin class.
Flight duration is usually an hour or two maximum, and space won’t be an issue as you will be too distracted by the some of the most breathtaking views in the world.